Direct calculation of anharmonic vibrational states of polyatomic molecules using density functional theory: spectroscopic tests of recently developed functionals

Wright, Nicholas J.; Gerber, R. Benny; Tozer, David J.

doi:10.1016/s0009-2614(00)00597-2

Cited by 38 publications

(38 citation statements)

References 24 publications

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“…When anharmonicity and coupling between modes are taken into account, the accuracy of BLYP frequencies worsens considerably. 40,41 We will return to this issue below in our discussion of vibrational spectra computed from the MD simulations.…”

Section: Resultsmentioning

confidence: 99%

Thermal Fluctuations of the Unusually Symmetric and Stable Superoxide Tetrahydrate Complex: An ab Initio Molecular Dynamics Study

Kuo

Tobias

2002

J. Phys. Chem. A

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We report an ab initio molecular dynamics simulation study of a complex composed of the superoxide anion and four water molecules. We probe the symmetry and stability of the superoxide tetrahydrate anion cluster at a low temperature (25 K) where there are vibrational spectra and a higher temperature (111 K) where experimental data are not available. From the ab initio simulation trajectory, we found the superoxide tetrahydrate complex to be highly symmetric, exhibiting a collective breathing motion on the picosecond time scale at low temperature that subsequently disappears at higher temperatures. Furthermore, we establish that superoxide tetrahydrate is a highly stable species at the higher temperature with little or no distortion to its geometry. The vibrational spectrum calculated from our ab initio trajectory is in reasonable agreement with experimental spectra, and we were able to assign individual peaks in the spectra to specific modes in the superoxide tetrahydrate anion cluster.

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Section: Resultsmentioning

confidence: 99%

Thermal Fluctuations of the Unusually Symmetric and Stable Superoxide Tetrahydrate Complex: An ab Initio Molecular Dynamics Study

Kuo

Tobias

2002

J. Phys. Chem. A

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“…28,73,[78][79][80][81][82][83][84][85][86][87][88][89][90][91][92][93] An effective way to treat medium-sized molecules uses second-order perturbation theory (PT2), which has been shown to give good results. 37-39,94-96 The PT2 approach, while less expensive than a more rigorous converged variational calculation, is still computationally expensive.…”

Section: Methodsmentioning

confidence: 99%

Prediction of Accurate Anharmonic Experimental Vibrational Frequencies for Water Clusters, (H₂O)_n, n = 2−5

2005

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Accurate anharmonic experimental vibrational frequencies for water clusters consisting of 2-5 water molecules have been predicted based on comparing different methods with MP2/aug-cc-pVTZ calculated and experimental anharmonic frequencies. The combination of using HF/6-31G* scaled frequencies for intramolecular modes and anharmonic frequencies for intermolecular modes gives excellent agreement with experiment for the water dimer and trimer, and are as good as the expensive anharmonic MP2 calculations. The water trimer, the cyclic C i and S 4 tetramers, and the cyclic pentamer all have unique peaks in the infrared spectrum between 500 and 800 cm -1 and between 3400 and 3700 cm -1 . Under the right experimental conditions these different clusters can be uniquely identified using high resolution IR spectroscopy.

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“…While the most advanced models are able to provide an accurate representation of the PES to obtain converged vibro-rotational levels; [46][47][48][49][50][51][52] for medium-to-large systems approximations are needed to make anharmonic calculations computationally feasible. Apart from improved empirical procedures based on transferable scaling factors in internal coordinates, the most successful methods are based on the vibrational self-consistent field (VSCF) [53][54][55][56][57][58][59][60][61] or VPT2. [62][63][64][65][66][67][68][69][70][71][72][73][74][75] The VPT2 approach is particularly appealing as it can provide accurate results at a reasonable computational price.…”

Section: Inclusion Of Anharmonicitymentioning

confidence: 99%

New Developments of a Multifrequency Virtual Spectrometer: Stereo‐Electronic, Dynamical, and Environmental Effects on Chiroptical Spectra

2014

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Computational spectroscopy has recently evolved from a field reserved for specialists toward a general tool allowing interpretations and analyses of experimental results. However, the current practice of providing tables of transitions for rigid geometries, possibly tuned by phenomenological broadening, is by far too naive. In order to improve this situation in the last few years we have been developing a general, robust, and user-friendly virtual spectrometer (VS) able to complement experimental studies for complex systems in condensed phases. The VS is based on flexible graphical pre- and postprocessing tools interfaced with general number-crunching software. This last tool is rooted in several electronic structure methodologies (DFT, TD-DFT, post-Hartree-Fock), powerful discrete/continuum models for describing environmental effects, and general vibrational and vibronic models. These last topics are the main focus of this work, which sketches our latest developments related to effective inclusion of anharmonic contributions, together with time-independent and/or time-dependent descriptions of vibronic transitions including Franck-Condon, Herzberg-Teller, and Duschinsky effects. Some test cases are described in some detail with the aim of showing the role of different effects in ruling vibrational (VCD) and electronic (ECD, CPL) chiral spectroscopies.

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Direct calculation of anharmonic vibrational states of polyatomic molecules using density functional theory: spectroscopic tests of recently developed functionals

Cited by 38 publications

References 24 publications

Thermal Fluctuations of the Unusually Symmetric and Stable Superoxide Tetrahydrate Complex: An ab Initio Molecular Dynamics Study

Thermal Fluctuations of the Unusually Symmetric and Stable Superoxide Tetrahydrate Complex: An ab Initio Molecular Dynamics Study

Prediction of Accurate Anharmonic Experimental Vibrational Frequencies for Water Clusters, (H₂O)_n, n = 2−5

New Developments of a Multifrequency Virtual Spectrometer: Stereo‐Electronic, Dynamical, and Environmental Effects on Chiroptical Spectra

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Direct calculation of anharmonic vibrational states of polyatomic molecules using density functional theory: spectroscopic tests of recently developed functionals

Cited by 38 publications

References 24 publications

Thermal Fluctuations of the Unusually Symmetric and Stable Superoxide Tetrahydrate Complex: An ab Initio Molecular Dynamics Study

Thermal Fluctuations of the Unusually Symmetric and Stable Superoxide Tetrahydrate Complex: An ab Initio Molecular Dynamics Study

Prediction of Accurate Anharmonic Experimental Vibrational Frequencies for Water Clusters, (H2O)n, n = 2−5

New Developments of a Multifrequency Virtual Spectrometer: Stereo‐Electronic, Dynamical, and Environmental Effects on Chiroptical Spectra

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Prediction of Accurate Anharmonic Experimental Vibrational Frequencies for Water Clusters, (H₂O)_n, n = 2−5